Gather ingredients: half a white onion with the skin removed, washed and cut into 4 pieces, 2 carrots washed and cut into 3 cm pieces, 3 celery sticks washed and cut into 3 cm pieces, the equivalent of 1 regular leek washed and cut into 3 cm pieces, 1/3 of a red bell pepper washed and cut into large pieces, 2 small slices of orange, a small handful of parsley, a few sprigs of thyme, 2 bay leaves (fresh or dried), 1 star anise, and 6 whole black peppercorns.
Place all ingredients in a 4 litre saucepan and add 3 litres of water.
Bring to a boil on high heat, then lower the heat to a gentle simmer. After 5 minutes, begin skimming off impurities with a ladle or spoon. Repeat as needed.
Simmer for 30 minutes, then turn off the heat and let it cool slightly.
Gather containers to store the stock and use tongs or a slotted spoon to distribute the vegetables evenly among the containers. Add the liquid, but not the orange slices.
Refrigerate the stock for 24-48 hours.
After 24-48 hours, remove the vegetables and the stock will last for around 5 days in the refrigerator.
To make the stock last longer, strain it into a saucepan and boil it until you have 1/10 of the original amount. For example, if you started with 1.2 litres, boil it down to 120ml.
Pour the concentrated stock carefully into an ice cube tray and freeze it to make your own stock cubes.